1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/interrupt.h>
5 #include <linux/spinlock.h>
6 #include <linux/list.h>
7 #include <linux/device.h>
9 #include <linux/debugfs.h>
10 #include <linux/seq_file.h>
11 #include <linux/gpio.h>
12 #include <linux/of_gpio.h>
13 #include <linux/idr.h>
14 #include <linux/slab.h>
15 #include <linux/acpi.h>
16 #include <linux/gpio/driver.h>
17 #include <linux/gpio/machine.h>
21 #define CREATE_TRACE_POINTS
22 #include <trace/events/gpio.h>
24 /* Implementation infrastructure for GPIO interfaces.
26 * The GPIO programming interface allows for inlining speed-critical
27 * get/set operations for common cases, so that access to SOC-integrated
28 * GPIOs can sometimes cost only an instruction or two per bit.
32 /* When debugging, extend minimal trust to callers and platform code.
33 * Also emit diagnostic messages that may help initial bringup, when
34 * board setup or driver bugs are most common.
36 * Otherwise, minimize overhead in what may be bitbanging codepaths.
39 #define extra_checks 1
41 #define extra_checks 0
44 /* gpio_lock prevents conflicts during gpio_desc[] table updates.
45 * While any GPIO is requested, its gpio_chip is not removable;
46 * each GPIO's "requested" flag serves as a lock and refcount.
48 DEFINE_SPINLOCK(gpio_lock);
50 static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
52 #define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)
54 static DEFINE_MUTEX(gpio_lookup_lock);
55 static LIST_HEAD(gpio_lookup_list);
56 LIST_HEAD(gpio_chips);
58 static inline void desc_set_label(struct gpio_desc *d, const char *label)
64 * Convert a GPIO number to its descriptor
66 struct gpio_desc *gpio_to_desc(unsigned gpio)
68 if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio))
71 return &gpio_desc[gpio];
73 EXPORT_SYMBOL_GPL(gpio_to_desc);
76 * Get the GPIO descriptor corresponding to the given hw number for this chip.
78 struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
81 if (hwnum >= chip->ngpio)
82 return ERR_PTR(-EINVAL);
84 return &chip->desc[hwnum];
88 * Convert a GPIO descriptor to the integer namespace.
89 * This should disappear in the future but is needed since we still
90 * use GPIO numbers for error messages and sysfs nodes
92 int desc_to_gpio(const struct gpio_desc *desc)
94 return desc - &gpio_desc[0];
96 EXPORT_SYMBOL_GPL(desc_to_gpio);
100 * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
101 * @desc: descriptor to return the chip of
103 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
105 return desc ? desc->chip : NULL;
107 EXPORT_SYMBOL_GPL(gpiod_to_chip);
109 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
110 static int gpiochip_find_base(int ngpio)
112 struct gpio_chip *chip;
113 int base = ARCH_NR_GPIOS - ngpio;
115 list_for_each_entry_reverse(chip, &gpio_chips, list) {
116 /* found a free space? */
117 if (chip->base + chip->ngpio <= base)
120 /* nope, check the space right before the chip */
121 base = chip->base - ngpio;
124 if (gpio_is_valid(base)) {
125 pr_debug("%s: found new base at %d\n", __func__, base);
128 pr_err("%s: cannot find free range\n", __func__);
134 * gpiod_get_direction - return the current direction of a GPIO
135 * @desc: GPIO to get the direction of
137 * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
139 * This function may sleep if gpiod_cansleep() is true.
141 int gpiod_get_direction(const struct gpio_desc *desc)
143 struct gpio_chip *chip;
145 int status = -EINVAL;
147 chip = gpiod_to_chip(desc);
148 offset = gpio_chip_hwgpio(desc);
150 if (!chip->get_direction)
153 status = chip->get_direction(chip, offset);
155 /* GPIOF_DIR_IN, or other positive */
157 /* FLAG_IS_OUT is just a cache of the result of get_direction(),
158 * so it does not affect constness per se */
159 clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
163 set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
167 EXPORT_SYMBOL_GPL(gpiod_get_direction);
170 * Add a new chip to the global chips list, keeping the list of chips sorted
173 * Return -EBUSY if the new chip overlaps with some other chip's integer
176 static int gpiochip_add_to_list(struct gpio_chip *chip)
178 struct list_head *pos = &gpio_chips;
179 struct gpio_chip *_chip;
182 /* find where to insert our chip */
183 list_for_each(pos, &gpio_chips) {
184 _chip = list_entry(pos, struct gpio_chip, list);
185 /* shall we insert before _chip? */
186 if (_chip->base >= chip->base + chip->ngpio)
190 /* are we stepping on the chip right before? */
191 if (pos != &gpio_chips && pos->prev != &gpio_chips) {
192 _chip = list_entry(pos->prev, struct gpio_chip, list);
193 if (_chip->base + _chip->ngpio > chip->base) {
195 "GPIO integer space overlap, cannot add chip\n");
201 list_add_tail(&chip->list, pos);
207 * gpiochip_add() - register a gpio_chip
208 * @chip: the chip to register, with chip->base initialized
209 * Context: potentially before irqs or kmalloc will work
211 * Returns a negative errno if the chip can't be registered, such as
212 * because the chip->base is invalid or already associated with a
213 * different chip. Otherwise it returns zero as a success code.
215 * When gpiochip_add() is called very early during boot, so that GPIOs
216 * can be freely used, the chip->dev device must be registered before
217 * the gpio framework's arch_initcall(). Otherwise sysfs initialization
218 * for GPIOs will fail rudely.
220 * If chip->base is negative, this requests dynamic assignment of
221 * a range of valid GPIOs.
223 int gpiochip_add(struct gpio_chip *chip)
228 int base = chip->base;
230 if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
236 spin_lock_irqsave(&gpio_lock, flags);
239 base = gpiochip_find_base(chip->ngpio);
247 status = gpiochip_add_to_list(chip);
250 chip->desc = &gpio_desc[chip->base];
252 for (id = 0; id < chip->ngpio; id++) {
253 struct gpio_desc *desc = &chip->desc[id];
256 /* REVISIT: most hardware initializes GPIOs as
257 * inputs (often with pullups enabled) so power
258 * usage is minimized. Linux code should set the
259 * gpio direction first thing; but until it does,
260 * and in case chip->get_direction is not set,
261 * we may expose the wrong direction in sysfs.
263 desc->flags = !chip->direction_input
269 spin_unlock_irqrestore(&gpio_lock, flags);
271 #ifdef CONFIG_PINCTRL
272 INIT_LIST_HEAD(&chip->pin_ranges);
275 of_gpiochip_add(chip);
276 acpi_gpiochip_add(chip);
281 status = gpiochip_export(chip);
285 pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__,
286 chip->base, chip->base + chip->ngpio - 1,
287 chip->label ? : "generic");
292 spin_unlock_irqrestore(&gpio_lock, flags);
294 /* failures here can mean systems won't boot... */
295 pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__,
296 chip->base, chip->base + chip->ngpio - 1,
297 chip->label ? : "generic");
300 EXPORT_SYMBOL_GPL(gpiochip_add);
302 /* Forward-declaration */
303 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);
306 * gpiochip_remove() - unregister a gpio_chip
307 * @chip: the chip to unregister
309 * A gpio_chip with any GPIOs still requested may not be removed.
311 int gpiochip_remove(struct gpio_chip *chip)
317 acpi_gpiochip_remove(chip);
319 spin_lock_irqsave(&gpio_lock, flags);
321 gpiochip_irqchip_remove(chip);
322 gpiochip_remove_pin_ranges(chip);
323 of_gpiochip_remove(chip);
325 for (id = 0; id < chip->ngpio; id++) {
326 if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {
332 for (id = 0; id < chip->ngpio; id++)
333 chip->desc[id].chip = NULL;
335 list_del(&chip->list);
338 spin_unlock_irqrestore(&gpio_lock, flags);
341 gpiochip_unexport(chip);
345 EXPORT_SYMBOL_GPL(gpiochip_remove);
348 * gpiochip_find() - iterator for locating a specific gpio_chip
349 * @data: data to pass to match function
350 * @callback: Callback function to check gpio_chip
352 * Similar to bus_find_device. It returns a reference to a gpio_chip as
353 * determined by a user supplied @match callback. The callback should return
354 * 0 if the device doesn't match and non-zero if it does. If the callback is
355 * non-zero, this function will return to the caller and not iterate over any
358 struct gpio_chip *gpiochip_find(void *data,
359 int (*match)(struct gpio_chip *chip,
362 struct gpio_chip *chip;
365 spin_lock_irqsave(&gpio_lock, flags);
366 list_for_each_entry(chip, &gpio_chips, list)
367 if (match(chip, data))
371 if (&chip->list == &gpio_chips)
373 spin_unlock_irqrestore(&gpio_lock, flags);
377 EXPORT_SYMBOL_GPL(gpiochip_find);
379 static int gpiochip_match_name(struct gpio_chip *chip, void *data)
381 const char *name = data;
383 return !strcmp(chip->label, name);
386 static struct gpio_chip *find_chip_by_name(const char *name)
388 return gpiochip_find((void *)name, gpiochip_match_name);
391 #ifdef CONFIG_GPIOLIB_IRQCHIP
394 * The following is irqchip helper code for gpiochips.
398 * gpiochip_add_chained_irqchip() - adds a chained irqchip to a gpiochip
399 * @gpiochip: the gpiochip to add the irqchip to
400 * @irqchip: the irqchip to add to the gpiochip
401 * @parent_irq: the irq number corresponding to the parent IRQ for this
403 * @parent_handler: the parent interrupt handler for the accumulated IRQ
404 * coming out of the gpiochip
406 void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
407 struct irq_chip *irqchip,
409 irq_flow_handler_t parent_handler)
411 if (gpiochip->can_sleep) {
412 chip_err(gpiochip, "you cannot have chained interrupts on a chip that may sleep\n");
417 * The parent irqchip is already using the chip_data for this
418 * irqchip, so our callbacks simply use the handler_data.
420 irq_set_handler_data(parent_irq, gpiochip);
421 irq_set_chained_handler(parent_irq, parent_handler);
423 EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);
426 * This lock class tells lockdep that GPIO irqs are in a different
427 * category than their parents, so it won't report false recursion.
429 static struct lock_class_key gpiochip_irq_lock_class;
432 * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip
433 * @d: the irqdomain used by this irqchip
434 * @irq: the global irq number used by this GPIO irqchip irq
435 * @hwirq: the local IRQ/GPIO line offset on this gpiochip
437 * This function will set up the mapping for a certain IRQ line on a
438 * gpiochip by assigning the gpiochip as chip data, and using the irqchip
439 * stored inside the gpiochip.
441 static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
442 irq_hw_number_t hwirq)
444 struct gpio_chip *chip = d->host_data;
446 irq_set_chip_data(irq, chip);
447 irq_set_lockdep_class(irq, &gpiochip_irq_lock_class);
448 irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
449 /* Chips that can sleep need nested thread handlers */
451 irq_set_nested_thread(irq, 1);
453 set_irq_flags(irq, IRQF_VALID);
455 irq_set_noprobe(irq);
458 * No set-up of the hardware will happen if IRQ_TYPE_NONE
459 * is passed as default type.
461 if (chip->irq_default_type != IRQ_TYPE_NONE)
462 irq_set_irq_type(irq, chip->irq_default_type);
467 static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
469 struct gpio_chip *chip = d->host_data;
472 set_irq_flags(irq, 0);
475 irq_set_nested_thread(irq, 0);
476 irq_set_chip_and_handler(irq, NULL, NULL);
477 irq_set_chip_data(irq, NULL);
480 static const struct irq_domain_ops gpiochip_domain_ops = {
481 .map = gpiochip_irq_map,
482 .unmap = gpiochip_irq_unmap,
483 /* Virtually all GPIO irqchips are twocell:ed */
484 .xlate = irq_domain_xlate_twocell,
487 static int gpiochip_irq_reqres(struct irq_data *d)
489 struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
491 if (gpio_lock_as_irq(chip, d->hwirq)) {
493 "unable to lock HW IRQ %lu for IRQ\n",
500 static void gpiochip_irq_relres(struct irq_data *d)
502 struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
504 gpio_unlock_as_irq(chip, d->hwirq);
507 static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
509 return irq_find_mapping(chip->irqdomain, offset);
513 * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip
514 * @gpiochip: the gpiochip to remove the irqchip from
516 * This is called only from gpiochip_remove()
518 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
522 acpi_gpiochip_free_interrupts(gpiochip);
524 /* Remove all IRQ mappings and delete the domain */
525 if (gpiochip->irqdomain) {
526 for (offset = 0; offset < gpiochip->ngpio; offset++)
527 irq_dispose_mapping(gpiochip->irq_base + offset);
528 irq_domain_remove(gpiochip->irqdomain);
531 if (gpiochip->irqchip) {
532 gpiochip->irqchip->irq_request_resources = NULL;
533 gpiochip->irqchip->irq_release_resources = NULL;
534 gpiochip->irqchip = NULL;
539 * gpiochip_irqchip_add() - adds an irqchip to a gpiochip
540 * @gpiochip: the gpiochip to add the irqchip to
541 * @irqchip: the irqchip to add to the gpiochip
542 * @first_irq: if not dynamically assigned, the base (first) IRQ to
543 * allocate gpiochip irqs from
544 * @handler: the irq handler to use (often a predefined irq core function)
545 * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE
546 * to have the core avoid setting up any default type in the hardware.
548 * This function closely associates a certain irqchip with a certain
549 * gpiochip, providing an irq domain to translate the local IRQs to
550 * global irqs in the gpiolib core, and making sure that the gpiochip
551 * is passed as chip data to all related functions. Driver callbacks
552 * need to use container_of() to get their local state containers back
553 * from the gpiochip passed as chip data. An irqdomain will be stored
554 * in the gpiochip that shall be used by the driver to handle IRQ number
555 * translation. The gpiochip will need to be initialized and registered
556 * before calling this function.
558 * This function will handle two cell:ed simple IRQs and assumes all
559 * the pins on the gpiochip can generate a unique IRQ. Everything else
560 * need to be open coded.
562 int gpiochip_irqchip_add(struct gpio_chip *gpiochip,
563 struct irq_chip *irqchip,
564 unsigned int first_irq,
565 irq_flow_handler_t handler,
568 struct device_node *of_node;
570 unsigned irq_base = 0;
572 if (!gpiochip || !irqchip)
575 if (!gpiochip->dev) {
576 pr_err("missing gpiochip .dev parent pointer\n");
579 of_node = gpiochip->dev->of_node;
580 #ifdef CONFIG_OF_GPIO
582 * If the gpiochip has an assigned OF node this takes precendence
583 * FIXME: get rid of this and use gpiochip->dev->of_node everywhere
585 if (gpiochip->of_node)
586 of_node = gpiochip->of_node;
588 gpiochip->irqchip = irqchip;
589 gpiochip->irq_handler = handler;
590 gpiochip->irq_default_type = type;
591 gpiochip->to_irq = gpiochip_to_irq;
592 gpiochip->irqdomain = irq_domain_add_simple(of_node,
593 gpiochip->ngpio, first_irq,
594 &gpiochip_domain_ops, gpiochip);
595 if (!gpiochip->irqdomain) {
596 gpiochip->irqchip = NULL;
599 irqchip->irq_request_resources = gpiochip_irq_reqres;
600 irqchip->irq_release_resources = gpiochip_irq_relres;
603 * Prepare the mapping since the irqchip shall be orthogonal to
604 * any gpiochip calls. If the first_irq was zero, this is
605 * necessary to allocate descriptors for all IRQs.
607 for (offset = 0; offset < gpiochip->ngpio; offset++) {
608 irq_base = irq_create_mapping(gpiochip->irqdomain, offset);
611 * Store the base into the gpiochip to be used when
612 * unmapping the irqs.
614 gpiochip->irq_base = irq_base;
617 acpi_gpiochip_request_interrupts(gpiochip);
621 EXPORT_SYMBOL_GPL(gpiochip_irqchip_add);
623 #else /* CONFIG_GPIOLIB_IRQCHIP */
625 static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}
627 #endif /* CONFIG_GPIOLIB_IRQCHIP */
629 #ifdef CONFIG_PINCTRL
632 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
633 * @chip: the gpiochip to add the range for
634 * @pinctrl: the dev_name() of the pin controller to map to
635 * @gpio_offset: the start offset in the current gpio_chip number space
636 * @pin_group: name of the pin group inside the pin controller
638 int gpiochip_add_pingroup_range(struct gpio_chip *chip,
639 struct pinctrl_dev *pctldev,
640 unsigned int gpio_offset, const char *pin_group)
642 struct gpio_pin_range *pin_range;
645 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
647 chip_err(chip, "failed to allocate pin ranges\n");
651 /* Use local offset as range ID */
652 pin_range->range.id = gpio_offset;
653 pin_range->range.gc = chip;
654 pin_range->range.name = chip->label;
655 pin_range->range.base = chip->base + gpio_offset;
656 pin_range->pctldev = pctldev;
658 ret = pinctrl_get_group_pins(pctldev, pin_group,
659 &pin_range->range.pins,
660 &pin_range->range.npins);
666 pinctrl_add_gpio_range(pctldev, &pin_range->range);
668 chip_dbg(chip, "created GPIO range %d->%d ==> %s PINGRP %s\n",
669 gpio_offset, gpio_offset + pin_range->range.npins - 1,
670 pinctrl_dev_get_devname(pctldev), pin_group);
672 list_add_tail(&pin_range->node, &chip->pin_ranges);
676 EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
679 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
680 * @chip: the gpiochip to add the range for
681 * @pinctrl_name: the dev_name() of the pin controller to map to
682 * @gpio_offset: the start offset in the current gpio_chip number space
683 * @pin_offset: the start offset in the pin controller number space
684 * @npins: the number of pins from the offset of each pin space (GPIO and
685 * pin controller) to accumulate in this range
687 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
688 unsigned int gpio_offset, unsigned int pin_offset,
691 struct gpio_pin_range *pin_range;
694 pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
696 chip_err(chip, "failed to allocate pin ranges\n");
700 /* Use local offset as range ID */
701 pin_range->range.id = gpio_offset;
702 pin_range->range.gc = chip;
703 pin_range->range.name = chip->label;
704 pin_range->range.base = chip->base + gpio_offset;
705 pin_range->range.pin_base = pin_offset;
706 pin_range->range.npins = npins;
707 pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
709 if (IS_ERR(pin_range->pctldev)) {
710 ret = PTR_ERR(pin_range->pctldev);
711 chip_err(chip, "could not create pin range\n");
715 chip_dbg(chip, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
716 gpio_offset, gpio_offset + npins - 1,
718 pin_offset, pin_offset + npins - 1);
720 list_add_tail(&pin_range->node, &chip->pin_ranges);
724 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
727 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
728 * @chip: the chip to remove all the mappings for
730 void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
732 struct gpio_pin_range *pin_range, *tmp;
734 list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
735 list_del(&pin_range->node);
736 pinctrl_remove_gpio_range(pin_range->pctldev,
741 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
743 #endif /* CONFIG_PINCTRL */
745 /* These "optional" allocation calls help prevent drivers from stomping
746 * on each other, and help provide better diagnostics in debugfs.
747 * They're called even less than the "set direction" calls.
749 static int __gpiod_request(struct gpio_desc *desc, const char *label)
751 struct gpio_chip *chip = desc->chip;
755 spin_lock_irqsave(&gpio_lock, flags);
757 /* NOTE: gpio_request() can be called in early boot,
758 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
761 if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
762 desc_set_label(desc, label ? : "?");
770 /* chip->request may sleep */
771 spin_unlock_irqrestore(&gpio_lock, flags);
772 status = chip->request(chip, gpio_chip_hwgpio(desc));
773 spin_lock_irqsave(&gpio_lock, flags);
776 desc_set_label(desc, NULL);
777 clear_bit(FLAG_REQUESTED, &desc->flags);
781 if (chip->get_direction) {
782 /* chip->get_direction may sleep */
783 spin_unlock_irqrestore(&gpio_lock, flags);
784 gpiod_get_direction(desc);
785 spin_lock_irqsave(&gpio_lock, flags);
788 spin_unlock_irqrestore(&gpio_lock, flags);
792 int gpiod_request(struct gpio_desc *desc, const char *label)
794 int status = -EPROBE_DEFER;
795 struct gpio_chip *chip;
798 pr_warn("%s: invalid GPIO\n", __func__);
806 if (try_module_get(chip->owner)) {
807 status = __gpiod_request(desc, label);
809 module_put(chip->owner);
814 gpiod_dbg(desc, "%s: status %d\n", __func__, status);
819 static bool __gpiod_free(struct gpio_desc *desc)
823 struct gpio_chip *chip;
827 gpiod_unexport(desc);
829 spin_lock_irqsave(&gpio_lock, flags);
832 if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
834 spin_unlock_irqrestore(&gpio_lock, flags);
835 might_sleep_if(chip->can_sleep);
836 chip->free(chip, gpio_chip_hwgpio(desc));
837 spin_lock_irqsave(&gpio_lock, flags);
839 desc_set_label(desc, NULL);
840 clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
841 clear_bit(FLAG_REQUESTED, &desc->flags);
842 clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
843 clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
847 spin_unlock_irqrestore(&gpio_lock, flags);
851 void gpiod_free(struct gpio_desc *desc)
853 if (desc && __gpiod_free(desc))
854 module_put(desc->chip->owner);
856 WARN_ON(extra_checks);
860 * gpiochip_is_requested - return string iff signal was requested
861 * @chip: controller managing the signal
862 * @offset: of signal within controller's 0..(ngpio - 1) range
864 * Returns NULL if the GPIO is not currently requested, else a string.
865 * The string returned is the label passed to gpio_request(); if none has been
866 * passed it is a meaningless, non-NULL constant.
868 * This function is for use by GPIO controller drivers. The label can
869 * help with diagnostics, and knowing that the signal is used as a GPIO
870 * can help avoid accidentally multiplexing it to another controller.
872 const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
874 struct gpio_desc *desc;
876 if (!GPIO_OFFSET_VALID(chip, offset))
879 desc = &chip->desc[offset];
881 if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
885 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
888 * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
889 * @desc: GPIO descriptor to request
890 * @label: label for the GPIO
892 * Function allows GPIO chip drivers to request and use their own GPIO
893 * descriptors via gpiolib API. Difference to gpiod_request() is that this
894 * function will not increase reference count of the GPIO chip module. This
895 * allows the GPIO chip module to be unloaded as needed (we assume that the
896 * GPIO chip driver handles freeing the GPIOs it has requested).
898 int gpiochip_request_own_desc(struct gpio_desc *desc, const char *label)
900 if (!desc || !desc->chip)
903 return __gpiod_request(desc, label);
905 EXPORT_SYMBOL_GPL(gpiochip_request_own_desc);
908 * gpiochip_free_own_desc - Free GPIO requested by the chip driver
909 * @desc: GPIO descriptor to free
911 * Function frees the given GPIO requested previously with
912 * gpiochip_request_own_desc().
914 void gpiochip_free_own_desc(struct gpio_desc *desc)
919 EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
921 /* Drivers MUST set GPIO direction before making get/set calls. In
922 * some cases this is done in early boot, before IRQs are enabled.
924 * As a rule these aren't called more than once (except for drivers
925 * using the open-drain emulation idiom) so these are natural places
926 * to accumulate extra debugging checks. Note that we can't (yet)
927 * rely on gpio_request() having been called beforehand.
931 * gpiod_direction_input - set the GPIO direction to input
932 * @desc: GPIO to set to input
934 * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
935 * be called safely on it.
937 * Return 0 in case of success, else an error code.
939 int gpiod_direction_input(struct gpio_desc *desc)
941 struct gpio_chip *chip;
942 int status = -EINVAL;
944 if (!desc || !desc->chip) {
945 pr_warn("%s: invalid GPIO\n", __func__);
950 if (!chip->get || !chip->direction_input) {
952 "%s: missing get() or direction_input() operations\n",
957 status = chip->direction_input(chip, gpio_chip_hwgpio(desc));
959 clear_bit(FLAG_IS_OUT, &desc->flags);
961 trace_gpio_direction(desc_to_gpio(desc), 1, status);
965 EXPORT_SYMBOL_GPL(gpiod_direction_input);
967 static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
969 struct gpio_chip *chip;
970 int status = -EINVAL;
972 /* GPIOs used for IRQs shall not be set as output */
973 if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
975 "%s: tried to set a GPIO tied to an IRQ as output\n",
980 /* Open drain pin should not be driven to 1 */
981 if (value && test_bit(FLAG_OPEN_DRAIN, &desc->flags))
982 return gpiod_direction_input(desc);
984 /* Open source pin should not be driven to 0 */
985 if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
986 return gpiod_direction_input(desc);
989 if (!chip->set || !chip->direction_output) {
991 "%s: missing set() or direction_output() operations\n",
996 status = chip->direction_output(chip, gpio_chip_hwgpio(desc), value);
998 set_bit(FLAG_IS_OUT, &desc->flags);
999 trace_gpio_value(desc_to_gpio(desc), 0, value);
1000 trace_gpio_direction(desc_to_gpio(desc), 0, status);
1005 * gpiod_direction_output_raw - set the GPIO direction to output
1006 * @desc: GPIO to set to output
1007 * @value: initial output value of the GPIO
1009 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
1010 * be called safely on it. The initial value of the output must be specified
1011 * as raw value on the physical line without regard for the ACTIVE_LOW status.
1013 * Return 0 in case of success, else an error code.
1015 int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
1017 if (!desc || !desc->chip) {
1018 pr_warn("%s: invalid GPIO\n", __func__);
1021 return _gpiod_direction_output_raw(desc, value);
1023 EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
1026 * gpiod_direction_output - set the GPIO direction to output
1027 * @desc: GPIO to set to output
1028 * @value: initial output value of the GPIO
1030 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
1031 * be called safely on it. The initial value of the output must be specified
1032 * as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1035 * Return 0 in case of success, else an error code.
1037 int gpiod_direction_output(struct gpio_desc *desc, int value)
1039 if (!desc || !desc->chip) {
1040 pr_warn("%s: invalid GPIO\n", __func__);
1043 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1045 return _gpiod_direction_output_raw(desc, value);
1047 EXPORT_SYMBOL_GPL(gpiod_direction_output);
1050 * gpiod_set_debounce - sets @debounce time for a @gpio
1051 * @gpio: the gpio to set debounce time
1052 * @debounce: debounce time is microseconds
1054 * returns -ENOTSUPP if the controller does not support setting
1057 int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
1059 struct gpio_chip *chip;
1061 if (!desc || !desc->chip) {
1062 pr_warn("%s: invalid GPIO\n", __func__);
1067 if (!chip->set || !chip->set_debounce) {
1069 "%s: missing set() or set_debounce() operations\n",
1074 return chip->set_debounce(chip, gpio_chip_hwgpio(desc), debounce);
1076 EXPORT_SYMBOL_GPL(gpiod_set_debounce);
1079 * gpiod_is_active_low - test whether a GPIO is active-low or not
1080 * @desc: the gpio descriptor to test
1082 * Returns 1 if the GPIO is active-low, 0 otherwise.
1084 int gpiod_is_active_low(const struct gpio_desc *desc)
1086 return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
1088 EXPORT_SYMBOL_GPL(gpiod_is_active_low);
1090 /* I/O calls are only valid after configuration completed; the relevant
1091 * "is this a valid GPIO" error checks should already have been done.
1093 * "Get" operations are often inlinable as reading a pin value register,
1094 * and masking the relevant bit in that register.
1096 * When "set" operations are inlinable, they involve writing that mask to
1097 * one register to set a low value, or a different register to set it high.
1098 * Otherwise locking is needed, so there may be little value to inlining.
1100 *------------------------------------------------------------------------
1102 * IMPORTANT!!! The hot paths -- get/set value -- assume that callers
1103 * have requested the GPIO. That can include implicit requesting by
1104 * a direction setting call. Marking a gpio as requested locks its chip
1105 * in memory, guaranteeing that these table lookups need no more locking
1106 * and that gpiochip_remove() will fail.
1108 * REVISIT when debugging, consider adding some instrumentation to ensure
1109 * that the GPIO was actually requested.
1112 static bool _gpiod_get_raw_value(const struct gpio_desc *desc)
1114 struct gpio_chip *chip;
1119 offset = gpio_chip_hwgpio(desc);
1120 value = chip->get ? chip->get(chip, offset) : false;
1121 trace_gpio_value(desc_to_gpio(desc), 1, value);
1126 * gpiod_get_raw_value() - return a gpio's raw value
1127 * @desc: gpio whose value will be returned
1129 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
1130 * its ACTIVE_LOW status.
1132 * This function should be called from contexts where we cannot sleep, and will
1133 * complain if the GPIO chip functions potentially sleep.
1135 int gpiod_get_raw_value(const struct gpio_desc *desc)
1139 /* Should be using gpio_get_value_cansleep() */
1140 WARN_ON(desc->chip->can_sleep);
1141 return _gpiod_get_raw_value(desc);
1143 EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
1146 * gpiod_get_value() - return a gpio's value
1147 * @desc: gpio whose value will be returned
1149 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
1152 * This function should be called from contexts where we cannot sleep, and will
1153 * complain if the GPIO chip functions potentially sleep.
1155 int gpiod_get_value(const struct gpio_desc *desc)
1160 /* Should be using gpio_get_value_cansleep() */
1161 WARN_ON(desc->chip->can_sleep);
1163 value = _gpiod_get_raw_value(desc);
1164 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1169 EXPORT_SYMBOL_GPL(gpiod_get_value);
1172 * _gpio_set_open_drain_value() - Set the open drain gpio's value.
1173 * @desc: gpio descriptor whose state need to be set.
1174 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1176 static void _gpio_set_open_drain_value(struct gpio_desc *desc, bool value)
1179 struct gpio_chip *chip = desc->chip;
1180 int offset = gpio_chip_hwgpio(desc);
1183 err = chip->direction_input(chip, offset);
1185 clear_bit(FLAG_IS_OUT, &desc->flags);
1187 err = chip->direction_output(chip, offset, 0);
1189 set_bit(FLAG_IS_OUT, &desc->flags);
1191 trace_gpio_direction(desc_to_gpio(desc), value, err);
1194 "%s: Error in set_value for open drain err %d\n",
1199 * _gpio_set_open_source_value() - Set the open source gpio's value.
1200 * @desc: gpio descriptor whose state need to be set.
1201 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
1203 static void _gpio_set_open_source_value(struct gpio_desc *desc, bool value)
1206 struct gpio_chip *chip = desc->chip;
1207 int offset = gpio_chip_hwgpio(desc);
1210 err = chip->direction_output(chip, offset, 1);
1212 set_bit(FLAG_IS_OUT, &desc->flags);
1214 err = chip->direction_input(chip, offset);
1216 clear_bit(FLAG_IS_OUT, &desc->flags);
1218 trace_gpio_direction(desc_to_gpio(desc), !value, err);
1221 "%s: Error in set_value for open source err %d\n",
1225 static void _gpiod_set_raw_value(struct gpio_desc *desc, bool value)
1227 struct gpio_chip *chip;
1230 trace_gpio_value(desc_to_gpio(desc), 0, value);
1231 if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
1232 _gpio_set_open_drain_value(desc, value);
1233 else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
1234 _gpio_set_open_source_value(desc, value);
1236 chip->set(chip, gpio_chip_hwgpio(desc), value);
1240 * gpiod_set_raw_value() - assign a gpio's raw value
1241 * @desc: gpio whose value will be assigned
1242 * @value: value to assign
1244 * Set the raw value of the GPIO, i.e. the value of its physical line without
1245 * regard for its ACTIVE_LOW status.
1247 * This function should be called from contexts where we cannot sleep, and will
1248 * complain if the GPIO chip functions potentially sleep.
1250 void gpiod_set_raw_value(struct gpio_desc *desc, int value)
1254 /* Should be using gpio_set_value_cansleep() */
1255 WARN_ON(desc->chip->can_sleep);
1256 _gpiod_set_raw_value(desc, value);
1258 EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
1261 * gpiod_set_value() - assign a gpio's value
1262 * @desc: gpio whose value will be assigned
1263 * @value: value to assign
1265 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1268 * This function should be called from contexts where we cannot sleep, and will
1269 * complain if the GPIO chip functions potentially sleep.
1271 void gpiod_set_value(struct gpio_desc *desc, int value)
1275 /* Should be using gpio_set_value_cansleep() */
1276 WARN_ON(desc->chip->can_sleep);
1277 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1279 _gpiod_set_raw_value(desc, value);
1281 EXPORT_SYMBOL_GPL(gpiod_set_value);
1284 * gpiod_cansleep() - report whether gpio value access may sleep
1285 * @desc: gpio to check
1288 int gpiod_cansleep(const struct gpio_desc *desc)
1292 return desc->chip->can_sleep;
1294 EXPORT_SYMBOL_GPL(gpiod_cansleep);
1297 * gpiod_to_irq() - return the IRQ corresponding to a GPIO
1298 * @desc: gpio whose IRQ will be returned (already requested)
1300 * Return the IRQ corresponding to the passed GPIO, or an error code in case of
1303 int gpiod_to_irq(const struct gpio_desc *desc)
1305 struct gpio_chip *chip;
1311 offset = gpio_chip_hwgpio(desc);
1312 return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
1314 EXPORT_SYMBOL_GPL(gpiod_to_irq);
1317 * gpio_lock_as_irq() - lock a GPIO to be used as IRQ
1318 * @chip: the chip the GPIO to lock belongs to
1319 * @offset: the offset of the GPIO to lock as IRQ
1321 * This is used directly by GPIO drivers that want to lock down
1322 * a certain GPIO line to be used for IRQs.
1324 int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
1326 if (offset >= chip->ngpio)
1329 if (test_bit(FLAG_IS_OUT, &chip->desc[offset].flags)) {
1331 "%s: tried to flag a GPIO set as output for IRQ\n",
1336 set_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
1339 EXPORT_SYMBOL_GPL(gpio_lock_as_irq);
1342 * gpio_unlock_as_irq() - unlock a GPIO used as IRQ
1343 * @chip: the chip the GPIO to lock belongs to
1344 * @offset: the offset of the GPIO to lock as IRQ
1346 * This is used directly by GPIO drivers that want to indicate
1347 * that a certain GPIO is no longer used exclusively for IRQ.
1349 void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
1351 if (offset >= chip->ngpio)
1354 clear_bit(FLAG_USED_AS_IRQ, &chip->desc[offset].flags);
1356 EXPORT_SYMBOL_GPL(gpio_unlock_as_irq);
1359 * gpiod_get_raw_value_cansleep() - return a gpio's raw value
1360 * @desc: gpio whose value will be returned
1362 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
1363 * its ACTIVE_LOW status.
1365 * This function is to be called from contexts that can sleep.
1367 int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
1369 might_sleep_if(extra_checks);
1372 return _gpiod_get_raw_value(desc);
1374 EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
1377 * gpiod_get_value_cansleep() - return a gpio's value
1378 * @desc: gpio whose value will be returned
1380 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
1383 * This function is to be called from contexts that can sleep.
1385 int gpiod_get_value_cansleep(const struct gpio_desc *desc)
1389 might_sleep_if(extra_checks);
1393 value = _gpiod_get_raw_value(desc);
1394 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1399 EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
1402 * gpiod_set_raw_value_cansleep() - assign a gpio's raw value
1403 * @desc: gpio whose value will be assigned
1404 * @value: value to assign
1406 * Set the raw value of the GPIO, i.e. the value of its physical line without
1407 * regard for its ACTIVE_LOW status.
1409 * This function is to be called from contexts that can sleep.
1411 void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
1413 might_sleep_if(extra_checks);
1416 _gpiod_set_raw_value(desc, value);
1418 EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
1421 * gpiod_set_value_cansleep() - assign a gpio's value
1422 * @desc: gpio whose value will be assigned
1423 * @value: value to assign
1425 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
1428 * This function is to be called from contexts that can sleep.
1430 void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
1432 might_sleep_if(extra_checks);
1436 if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
1438 _gpiod_set_raw_value(desc, value);
1440 EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
1443 * gpiod_add_lookup_table() - register GPIO device consumers
1444 * @table: table of consumers to register
1446 void gpiod_add_lookup_table(struct gpiod_lookup_table *table)
1448 mutex_lock(&gpio_lookup_lock);
1450 list_add_tail(&table->list, &gpio_lookup_list);
1452 mutex_unlock(&gpio_lookup_lock);
1455 static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
1457 enum gpio_lookup_flags *flags)
1459 static const char *suffixes[] = { "gpios", "gpio" };
1460 char prop_name[32]; /* 32 is max size of property name */
1461 enum of_gpio_flags of_flags;
1462 struct gpio_desc *desc;
1465 for (i = 0; i < ARRAY_SIZE(suffixes); i++) {
1467 snprintf(prop_name, 32, "%s-%s", con_id, suffixes[i]);
1469 snprintf(prop_name, 32, "%s", suffixes[i]);
1471 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
1473 if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER))
1480 if (of_flags & OF_GPIO_ACTIVE_LOW)
1481 *flags |= GPIO_ACTIVE_LOW;
1486 static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
1488 enum gpio_lookup_flags *flags)
1490 struct acpi_gpio_info info;
1491 struct gpio_desc *desc;
1493 desc = acpi_get_gpiod_by_index(dev, idx, &info);
1497 if (info.gpioint && info.active_low)
1498 *flags |= GPIO_ACTIVE_LOW;
1503 static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
1505 const char *dev_id = dev ? dev_name(dev) : NULL;
1506 struct gpiod_lookup_table *table;
1508 mutex_lock(&gpio_lookup_lock);
1510 list_for_each_entry(table, &gpio_lookup_list, list) {
1511 if (table->dev_id && dev_id) {
1513 * Valid strings on both ends, must be identical to have
1516 if (!strcmp(table->dev_id, dev_id))
1520 * One of the pointers is NULL, so both must be to have
1523 if (dev_id == table->dev_id)
1530 mutex_unlock(&gpio_lookup_lock);
1534 static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
1536 enum gpio_lookup_flags *flags)
1538 struct gpio_desc *desc = ERR_PTR(-ENOENT);
1539 struct gpiod_lookup_table *table;
1540 struct gpiod_lookup *p;
1542 table = gpiod_find_lookup_table(dev);
1546 for (p = &table->table[0]; p->chip_label; p++) {
1547 struct gpio_chip *chip;
1549 /* idx must always match exactly */
1553 /* If the lookup entry has a con_id, require exact match */
1554 if (p->con_id && (!con_id || strcmp(p->con_id, con_id)))
1557 chip = find_chip_by_name(p->chip_label);
1560 dev_err(dev, "cannot find GPIO chip %s\n",
1562 return ERR_PTR(-ENODEV);
1565 if (chip->ngpio <= p->chip_hwnum) {
1567 "requested GPIO %d is out of range [0..%d] for chip %s\n",
1568 idx, chip->ngpio, chip->label);
1569 return ERR_PTR(-EINVAL);
1572 desc = gpiochip_get_desc(chip, p->chip_hwnum);
1582 * gpiod_get - obtain a GPIO for a given GPIO function
1583 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1584 * @con_id: function within the GPIO consumer
1585 * @flags: optional GPIO initialization flags
1587 * Return the GPIO descriptor corresponding to the function con_id of device
1588 * dev, -ENOENT if no GPIO has been assigned to the requested function, or
1589 * another IS_ERR() code if an error occured while trying to acquire the GPIO.
1591 struct gpio_desc *__must_check __gpiod_get(struct device *dev, const char *con_id,
1592 enum gpiod_flags flags)
1594 return gpiod_get_index(dev, con_id, 0, flags);
1596 EXPORT_SYMBOL_GPL(__gpiod_get);
1599 * gpiod_get_optional - obtain an optional GPIO for a given GPIO function
1600 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1601 * @con_id: function within the GPIO consumer
1602 * @flags: optional GPIO initialization flags
1604 * This is equivalent to gpiod_get(), except that when no GPIO was assigned to
1605 * the requested function it will return NULL. This is convenient for drivers
1606 * that need to handle optional GPIOs.
1608 struct gpio_desc *__must_check __gpiod_get_optional(struct device *dev,
1610 enum gpiod_flags flags)
1612 return gpiod_get_index_optional(dev, con_id, 0, flags);
1614 EXPORT_SYMBOL_GPL(__gpiod_get_optional);
1617 * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
1618 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1619 * @con_id: function within the GPIO consumer
1620 * @idx: index of the GPIO to obtain in the consumer
1621 * @flags: optional GPIO initialization flags
1623 * This variant of gpiod_get() allows to access GPIOs other than the first
1624 * defined one for functions that define several GPIOs.
1626 * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the
1627 * requested function and/or index, or another IS_ERR() code if an error
1628 * occured while trying to acquire the GPIO.
1630 struct gpio_desc *__must_check __gpiod_get_index(struct device *dev,
1633 enum gpiod_flags flags)
1635 struct gpio_desc *desc = NULL;
1637 enum gpio_lookup_flags lookupflags = 0;
1639 dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
1641 /* Using device tree? */
1642 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
1643 dev_dbg(dev, "using device tree for GPIO lookup\n");
1644 desc = of_find_gpio(dev, con_id, idx, &lookupflags);
1645 } else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) {
1646 dev_dbg(dev, "using ACPI for GPIO lookup\n");
1647 desc = acpi_find_gpio(dev, con_id, idx, &lookupflags);
1651 * Either we are not using DT or ACPI, or their lookup did not return
1652 * a result. In that case, use platform lookup as a fallback.
1654 if (!desc || desc == ERR_PTR(-ENOENT)) {
1655 dev_dbg(dev, "using lookup tables for GPIO lookup");
1656 desc = gpiod_find(dev, con_id, idx, &lookupflags);
1660 dev_dbg(dev, "lookup for GPIO %s failed\n", con_id);
1664 status = gpiod_request(desc, con_id);
1667 return ERR_PTR(status);
1669 if (lookupflags & GPIO_ACTIVE_LOW)
1670 set_bit(FLAG_ACTIVE_LOW, &desc->flags);
1671 if (lookupflags & GPIO_OPEN_DRAIN)
1672 set_bit(FLAG_OPEN_DRAIN, &desc->flags);
1673 if (lookupflags & GPIO_OPEN_SOURCE)
1674 set_bit(FLAG_OPEN_SOURCE, &desc->flags);
1676 /* No particular flag request, return here... */
1677 if (!(flags & GPIOD_FLAGS_BIT_DIR_SET))
1681 if (flags & GPIOD_FLAGS_BIT_DIR_OUT)
1682 status = gpiod_direction_output(desc,
1683 flags & GPIOD_FLAGS_BIT_DIR_VAL);
1685 status = gpiod_direction_input(desc);
1688 dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
1690 return ERR_PTR(status);
1695 EXPORT_SYMBOL_GPL(__gpiod_get_index);
1698 * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO
1700 * @dev: GPIO consumer, can be NULL for system-global GPIOs
1701 * @con_id: function within the GPIO consumer
1702 * @index: index of the GPIO to obtain in the consumer
1703 * @flags: optional GPIO initialization flags
1705 * This is equivalent to gpiod_get_index(), except that when no GPIO with the
1706 * specified index was assigned to the requested function it will return NULL.
1707 * This is convenient for drivers that need to handle optional GPIOs.
1709 struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
1712 enum gpiod_flags flags)
1714 struct gpio_desc *desc;
1716 desc = gpiod_get_index(dev, con_id, index, flags);
1718 if (PTR_ERR(desc) == -ENOENT)
1724 EXPORT_SYMBOL_GPL(__gpiod_get_index_optional);
1727 * gpiod_put - dispose of a GPIO descriptor
1728 * @desc: GPIO descriptor to dispose of
1730 * No descriptor can be used after gpiod_put() has been called on it.
1732 void gpiod_put(struct gpio_desc *desc)
1736 EXPORT_SYMBOL_GPL(gpiod_put);
1738 #ifdef CONFIG_DEBUG_FS
1740 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
1743 unsigned gpio = chip->base;
1744 struct gpio_desc *gdesc = &chip->desc[0];
1748 for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
1749 if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
1752 gpiod_get_direction(gdesc);
1753 is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
1754 is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags);
1755 seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s",
1757 is_out ? "out" : "in ",
1759 ? (chip->get(chip, i) ? "hi" : "lo")
1761 is_irq ? "IRQ" : " ");
1762 seq_printf(s, "\n");
1766 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
1768 unsigned long flags;
1769 struct gpio_chip *chip = NULL;
1770 loff_t index = *pos;
1774 spin_lock_irqsave(&gpio_lock, flags);
1775 list_for_each_entry(chip, &gpio_chips, list)
1777 spin_unlock_irqrestore(&gpio_lock, flags);
1780 spin_unlock_irqrestore(&gpio_lock, flags);
1785 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
1787 unsigned long flags;
1788 struct gpio_chip *chip = v;
1791 spin_lock_irqsave(&gpio_lock, flags);
1792 if (list_is_last(&chip->list, &gpio_chips))
1795 ret = list_entry(chip->list.next, struct gpio_chip, list);
1796 spin_unlock_irqrestore(&gpio_lock, flags);
1804 static void gpiolib_seq_stop(struct seq_file *s, void *v)
1808 static int gpiolib_seq_show(struct seq_file *s, void *v)
1810 struct gpio_chip *chip = v;
1813 seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
1814 chip->base, chip->base + chip->ngpio - 1);
1817 seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
1820 seq_printf(s, ", %s", chip->label);
1821 if (chip->can_sleep)
1822 seq_printf(s, ", can sleep");
1823 seq_printf(s, ":\n");
1826 chip->dbg_show(s, chip);
1828 gpiolib_dbg_show(s, chip);
1833 static const struct seq_operations gpiolib_seq_ops = {
1834 .start = gpiolib_seq_start,
1835 .next = gpiolib_seq_next,
1836 .stop = gpiolib_seq_stop,
1837 .show = gpiolib_seq_show,
1840 static int gpiolib_open(struct inode *inode, struct file *file)
1842 return seq_open(file, &gpiolib_seq_ops);
1845 static const struct file_operations gpiolib_operations = {
1846 .owner = THIS_MODULE,
1847 .open = gpiolib_open,
1849 .llseek = seq_lseek,
1850 .release = seq_release,
1853 static int __init gpiolib_debugfs_init(void)
1855 /* /sys/kernel/debug/gpio */
1856 (void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
1857 NULL, NULL, &gpiolib_operations);
1860 subsys_initcall(gpiolib_debugfs_init);
1862 #endif /* DEBUG_FS */